public function handle($data)
 {
     $this->validate_request(["permission"]);
     $profile = GroupBackend::fetch_group_profile($this->params["id"]);
     $permission = $data->{"permission"};
     GroupBackend::set_group_permission($profile, $permission, true);
     return ["user" => $profile->toExternalForm(), "permission" => $permission];
 }
 public function handleDelete($data)
 {
     $profile = GroupBackend::fetch_group_profile($this->params["id"]);
     GroupBackend::set_group_permission($profile, $this->params["permission"], true);
     return [];
 }